Methods and apparatus of this type are known for example from WO 98/20360 of from PCT/EP03/01192. In this case, multidimensional data sets are generated in order to image multidimensional objects, such as for example the heart or liver of a human, the surface of a semiconductor or the weld seam of a packaging. Such multidimensional data sets are generated by recording the object by a suitable recording process, such as for example an x-ray image, an ultrasound image or nuclear spin tomography. To generate a three-dimensional image data set for example, the reconstruction and assembly of one- or two-dimensional image data which have been generated by suitable images is carried out. In the case of an ultrasound image, with the aid of an ultrasound recording apparatus, two-dimensional ultrasound images known as image subdomains are recorded and are so arranged in order in a three-dimensional image data set that the two-dimensional image subdomains supply the relative arrangement of the image data with the correct orientation for the individual three-dimensional image data cubes (known as voxels) of the volume data set.
Such image subdomains generated by two-dimensional recording processes normally correspond to a line-by-line scanning operation, which records the object line by line in a recording direction in which the x-ray machine or e.g. the ultrasound transmitter is moved. The image subdomains generated in the recording apparatus can be transferred digitally or via a video output into a reprocessing apparatus or into a data processing system. There, the two-dimensional images can be stored or directly reprocessed by stacking the individual layers or slices of the object one over another or lining them up next to one another, in order then to obtain for example a three-dimensional representation of the object on the display apparatus.
If the object is a moving object, the corresponding two-dimensional image subdomains can also be provided with an associated time datum, so that each image subdomain can be allocated to a specific state of motion of the object. By means of this time datum, three-dimensional image data sets can be generated which also have corresponding time data. This is known as a four-dimensional data set. A three-dimensional moving object (e.g. the heart of a human) can be shown moving on the screen of a data processing apparatus (i.e. in four dimensions) by showing the three-dimensional image data sets provided with the time data staggered in time sequence.
As soon as a three- or four-dimensional image data set is being dealt with, this can be shown for example on the screen of a data processing apparatus. In all probability, however, the observer of such an image would like to look more closely at certain interesting areas of the object, e.g. the valve of a heart, the solder point of a semiconductor structural element on the printed circuit board, or the point of adhesion of a packaging. In this case, it is known that the observer, by selecting usually two-dimensional planes of section through the three-dimensional data set, will analyse the predeterminable region by making various planes of section through the predeterminable region and will manipulate these successively until he obtains the desired section representation.
Such a procedure has the disadvantage, however, that “navigation” through the multidimensional data set by means of a usually two-dimensional plane of section is time-consuming, since the plane has to be adjusted by repeated manipulation until the section through the multidimensional data set, e.g. through the volume, offers the corresponding desired view. For example, such a procedure in the case of medical data is often very long-winded and involved, as plural stages (of manipulation) are necessary in order to “cut clear” the appropriate point of interest, i.e. the predeterminable region, and to make it visible.